The research team followed and collected data from 19,486 patients with inflamatory bowel disease enrolled in Cancers et Surrisque Associé aux Maladies Inflammatoires Intestinales En France from 2004 to 2005, and followed them until 2007.

When the study began, 2841 patients were characterized as having long-standing extensive colitis.

Early lesions high-grade dysplasia and colorectal cancer were defined as those diagnosed within 10 years after diagnosis of inflammatory bowel disease.

The standardized incidence ratios of colorectal cancer were 2.2 for all IBD patients

Gastroenterology

The researchers evaluated 37 patients that developed colorectal cancer during the follow-up period, and 20 developed colorectal higher-grade dysplasia.

The standardized incidence ratios of colorectal cancer were 2.2 for all inflammatory bowel disease patients, 7.0 for patients with long-standing extensive colitis, and 1.1 for patients without long-standing extensive colitis.

Among patients with long-standing extensive colitis, the multivariate adjusted hazard ratio for colorectal high-grade dysplasia and cancer was 0.28 for those who received thiopurines compared with those who never received thiopurine therapy.

The team observed that 22 patients developed early lesions.

The research team noted that 7 of these were related to inflammatory bowel disease, based on histologic analysis.

Dr Beaugerie's team comments, "Patients with IBD and long-standing extensive colitis are at increased risk for colorectal cancer, although the risk is lower among patients receiving thiopurine therapy."

"Patients without long-standing extensive colitis have a risk for colorectal cancer similar to that of the general population, but they can develop inflammatory bowel disease-related lesions within 10 years after diagnosis of inflamatory bowel disease."